The effectiveness of tobramycin and Ocuflox in a prophylaxis model of Staphylococcus keratitis.

Abstract

PURPOSE:

To determine the effectiveness of prophylactic antibiotic treatment prior to intra-corneal infection with Staphylococcus aureus.

METHODS:

One topical drop of Tobrex (0.3% tobramycin), tobramycin (0.3%) in the Tobrex vehicle with 0.05% dodecyl maltoside (DDM)/4.0% hydroxypropylmethycellulose (HPMC), Ocuflox (0.3% ofloxacin) or DDM/HPMC vehicle were applied to rabbit eyes at one or five hours prior to injection of bacteria. Approximately 500 colony-forming units (CFU) of S. aureus strain 8325-4 were injected into the corneal stroma. Rabbits were sacrificed five hours after infection and corneal homogenates were cultured to determine the number of colony forming units (CFU) per cornea.

RESULTS:

Rabbits treated at five hours prior to infection with tobramycin-DDM/HPMC reduced the bacterial load by approximately 2.4 log CFU/cornea as compared to the untreated control (3.47 +/- 0.98 vs. 5.71 +/- 0.14 log CFU/cornea, respectively; P = 0.0010); however, Ocuflox, Tobrex, or DDM/HPMC vehicle did not significantly reduce the log CFU (P >or= 0.4837). Rabbits treated at 1 hour prior to infection with Ocuflox or tobramycin-DDM/HPMC had significantly reduced CFU/cornea (1.31 +/- 0.86 and 0.48 +/- 0.31 log CFU/cornea, respectively) as compared to the untreated group (5.71 +/- 0.14 log CFU/cornea; P <or= 0.0001). Neither Tobrex nor the DDM/HPMC vehicle significantly reduced the CFU/cornea compared to the untreated group (P >or= 0.2312).

CONCLUSIONS:

This pre-treatment model of Staphylococcus keratitis quantitatively measured the prophylactic effectiveness of topical antibiotic formulations. An important finding was that a tobramycin-DDM/HPMC formulation was highly effective as a prophylactic medication.

• Authors: J J Dajcs, J M Moreau, D W Stroman, B A Schlech, T L Ke, B A Thibodeaux, D O Girgis, A R Caballero, R J O'Callaghan
• Journal: Current eye research (Curr Eye Res) Vol. 23 Issue 1 Pg. 60-3 (Jul 2001) ISSN: 0271-3683 [Print] England
• PMID: 11821987 (Publication Type: Comparative Study, Journal Article, Research Support, Non-U.S. Gov't, Research Support, U.S. Gov't, P.H.S.)

Chemical References

• Anti-Bacterial Agents
• Anti-Infective Agents
• Ophthalmic Solutions
• Ofloxacin
• Tobramycin

Topics

• Animals
• Anti-Bacterial Agents (administration & dosage, therapeutic use)
• Anti-Infective Agents (administration & dosage, therapeutic use)
• Antibiotic Prophylaxis
• Colony Count, Microbial
• Corneal Stroma (microbiology)
• Eye Infections, Bacterial (drug therapy, microbiology)
• Keratitis (drug therapy, microbiology)
• Microbial Sensitivity Tests
• Ofloxacin (administration & dosage, therapeutic use)
• Ophthalmic Solutions
• Rabbits
• Staphylococcal Infections (drug therapy, microbiology)
• Staphylococcus aureus (isolation & purification)
• Tobramycin (administration & dosage, therapeutic use)